Age-related Macular Degeneration Linked To Low Antioxidant Levels And Sunlight Exposure

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Main Category: Eye Health / Blindness
Also Included In: Nutrition / Diet
Article Date: 16 Oct 2008 - 0:00 PDT

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Some types of the age-related macular degeneration (AMD) have been linked to low plasma levels of antioxidants and blue light exposure from the sun, according to researchers from Europe who published a paper in the October issue of Archives of Ophthalmology.

"The retina is vulnerable to the damaging effects of light," write author Astrid E. Fletcher, Ph.D. (London School of Hygiene & Tropical Medicine) and colleagues. "While wavelengths in the UV radiation range are largely absorbed by the cornea and lens, the retina is exposed to visible light, including blue light." According to previous animal and laboratory studies, it is possible that blue light can damage the retina and lead to a deterioration of the area of the retina responsible for sharp vision (the macula); this is called AMD.

It is hypothesized that the body can use antioxidant enzymes such as vitamins C and E, the carotenoids (lutein and zeaxanthin), and zinc to protect the retina from blue light's harmful effects. Fletcher and colleagues analyzed the blood of 4,573 older adults who were about 73.2 years of age, and took measurements of the levels of these nutrients. Participants, who were all part of the European Eye Study, also answered questions regarding lifetime sunlight exposure and had photographs taken of their retinas to test for AMD.

AMD was not found in 2,117 of the 4,400 participants with complete information who were included in the analysis sample. Neovascular AMD (and advanced form with new blood vessels formed) was found in 101 participants and early-stage AMD was noted in 2,182 participants. The researchers did not find a link between either form of AMD and blue light exposure. However, in individuals who were in the lowest quarter of antioxidant levels, blue light exposure was associated with neovascular AMD. "In particular, the combination of blue light exposure in the presence of low levels of zeaxanthin, alpha-tocopherol [vitamin E] and vitamin C was associated with a nearly four-fold odds ratio of neovascular AMD," write Fletcher and colleagues.

The researchers recommend that people consume key antioxidants by ingesting appropriate amounts of vitamin C, zinc, and carotenoid-rich fruits and vegetables. Further, they reiterate the standard precaution of wearing broad-rimmed hats and sunglasses to reduce the exposure of the retina to blue light.

They conclude that, "In the absence of cost-effective screening methods to identify people in the population with early AMD, we suggest that recommendations on ocular protection and diet target the general population, especially middle-aged people."

Sunlight Exposure, Antioxidants, and Age-Related Macular Degeneration
Astrid E. Fletcher, PhD; Graham C. Bentham, PhD; Maureen Agnew, PhD; Ian S. Young, MD, PhD; Cristina Augood, MBBS; Usha Chakravarthy, MD, PhD; Paulus T. V. M. de Jong, MD, PhD; Mati Rahu, PhD; Johan Seland, MD; Gisele Soubrane, MD, PhD; Laura Tomazzoli, MD; Fotis Topouzis, MD; Johannes R. Vingerling, MD, PhD; Jesus Vioque, PhD
Archives of Ophthalmology (2008). 126(10):1396-1403.
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Written by: Peter M Crosta
Copyright: Medical News Today
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